


Let's Get Physical

by mylifeisloki



Category: Captain America (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: F/M, Romanogers Smut Week, Shower Sex, Tumblr Prompt, personal trainer au
Language: English
Status: Completed
Published: 2016-03-24
Updated: 2016-03-24
Packaged: 2018-05-28 20:55:24
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,662
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6344827
Author URL: https://archiveofourown.org/users/mylifeisloki/pseuds/mylifeisloki
Summary: <blockquote class="userstuff">
              <p>When Steve's personal trainer is called away in an emergency, Natasha fills in and makes sure he gets the best workout of his life.</p>
            </blockquote>





	Let's Get Physical

The minute Steve laid eyes on Thor he knew that he’d made the right decision when it came to getting a personal trainer. The minute Steve laid eyes on the pretty female trainer across the gym, he questioned his sense of decency because he wanted to switch immediately no matter how many questions he’d get. But Steve was a well-mannered guy with no desire to cause a scene, so he stuck with Thor.

And hey, it wasn’t like Thor was nothing to look at. The guy had at least twenty or thirty pounds on Steve and his muscles were the kind of defined that the ex-soldier could have sworn were only seen in magazines. He was handsome and knew what he was doing and that was great, but he wasn’t Natasha. He wasn’t the redhead who whipped the girls, and several lucky guys, into shape. God, Steve was so hot for her it was ridiculous.

“You’re not paying any attention, are you?”

What? Steve snapped out of it and realized that he was only halfway through a bench, so he completed it and lowered the bar in the hopes that Thor might take that as good enough. Nope.

“Do it again. I want ten reps at this weight.”

Now, Thor’s whole job was to push him. Steve had signed up for this knowing that he wasn’t going to get the baby treatment, but he _almost_ pouted and asked Thor whether or not he understood that having Natasha (who was dressed in a pair of black tights and a matching sports bra because the whole world hated Steve) right there was probably some kind of liability.

Steve had been seeing Thor at the gym for three weeks now, four times a week. He kept his appointments in the afternoon, for the most part, and absolutely did not adjust to a slightly earlier time when he learned of Natasha’s schedule there. As far as he was concerned, that never happened. The Swede, whom Steve had come to consider a friend (albeit a friend who worked him to the point of exhaustion every time they saw one another), was the kind of man who could tell Steve to do another rep, another set, more weight... and do it with a huge smile on his face. He didn't compromise and Steve found that he rather liked that particular trait.

Usually, they started off with some stretching and moved on to the free weights, then they'd spend some time on machines (including the bench press, where Thor would consistently push him to beat his current max), then came push-ups and sit-ups and crunches and squats, and finally they cooled down with either more stretching or a punching bag that Steve went at without really looking at it. His gaze was usually on Natasha, truth be told.

Because Natasha was beautiful, but it was more than that. There was this girl who would come in for appointments with Natasha- a girl that Steve sometimes caught looking at _him_ the way he would look at Natasha. And it was great to see that the redhead knew what she was doing and did her best to help her clients, but it was when she had appointments with men that Steve got hot under the collar. There was just something about watching Natasha, who couldn't have been more than 5'4'' if that, bossing around a guy twice her size and three heads taller. Maybe that was just Steve's _thing_. Maybe he was just a perv.

Pulling himself off the bench press, Steve listened to Thor's direction and fell forwards for his push-ups, counting to himself until Thor told him to get louder. “Seven,” he panted. “Eight. Nine. Ten.” That went on for a while until he reached a number high enough to satisfy his tormentor, and then he was instructed to turn over for sit-ups. Again, he counted. “Eleven. Twelve. Thirteen. Fourteen.” Then crunches. “Fifteen. Sixteen-- fuck. Seventeen. Eighteen.” With at least thirty of each, Steve fell back to breathe for a second, Thor's watchful eye on him as always.

“You still have squats to do,” he pointed out, looking down at the soldier. “You'd better get up before everyone here sees you giving up like this.”

Shit. Right. Steve hopped up and began his squats, glancing over to Natasha's side of the gym with no shortage of interest. She was currently standing with her arms crossed over her chest, one hip jutting out as she urged on a huge man in front of her who was trying to get through a set of push-ups himself. Lucky bastard.

Thor seemed to finally catch on, his eyes darting from Steve to Natasha and back again. Getting the picture, he stepped closer and lowered his voice. “You want her to notice you?” He asked. “Then you'd better step it up. Natasha's not going to notice someone who gives up like you do.” Uh oh. Steve felt like that was a challenge if he'd ever heard one, and he set his jaw as he finished his squats and flexed his hands.

“Punching bag.”

Smirking triumphantly, Thor led him over to the bag and Steve quickly taped his hands before he went at it, punching hard and grunting with the exertion. He was so going to feel this in the morning, but he knew it would leave him with a good feeling this evening.. It was worth it, in the end. By the time he was beginning to slow down, Thor berating him for most of the time, Steve had also noticed that Natasha's session had ended. For the first time since he'd been coming there, she wandered over to Thor and stood beside him, hands in the pockets of the red hoodie she'd pulled on.

“Nice form,” she commented, looking Steve over.

That was all. That was the only thing she said, leaving once she'd exchanged a meaningful look with Thor. Steve was hooked and _so_ distracted that his punches ceased for a moment as she walked away and the bag hit him right in the face- something he tried and failed to recover from with any dignity or grace. “Good session today,” Thor sighed, shaking his head. “Again on Monday?”

Steve nodded. “Yeah, definitely,” he said quickly. “See you Monday, man.” With that, he headed into the locker rooms to shower and change, but despite his wishes to see Natasha again before he left, she was nowhere to be found.

For a while, they continued like that- with Thor using Natasha as motivation for Steve's workouts. If the soldier was lucky, Natasha would stop by every now and then to comment on his posture or praise Thor for the improvement of his clients. She made a vague comment about how Steve's presence served as motivation for _her_ clients and Steve had to bite his tongue to keep from saying anything.

A month later, Steve walked into the gym with his bag in hand, ready to get to work. He changed as usual, selecting a pair of navy sweatpants and a white tshirt, and headed out to the main part of the gym to meet Thor-- but Thor wasn't there. Instead, he found himself towering over Natasha herself. She was wearing black again today; a black tank top and black tights, along with a pink hoodie, and she looked amazing.

“Hey,” he greeted slowly, awkwardly stopping in front of her with his towel slung over one shoulder. “Where's Thor?”

Natasha sighed. “Family emergency,” she explained. “He had to get back to Sweden for a little while, so I'm covering most of his clients.”

Uh oh. This was not good. “Oh, well.. If you're busy, I can just work out on my own...”

“And let Thor's star client take a couple of steps back? He'd kill me.” Pulling her sweater off, she left it draped over a chair near the desk and gestured for him to step onto the mat as usual. “We're going to start with some stretching.”

Steve just kept telling himself that he was a gentleman. He didn't have to be inappropriate. Following her onto the mat, he set down his towel and began stretching the way Thor taught him to- bending down to touch his toes, then move on to lunges. But she stopped him. “Straighten your back a little bit,” she said, stepping up behind him and laying her hand on his lower back to guide him. “And your shoulders too.”

She was touching him. Steve did as he was told, letting Natasha guide him through his lunges. After that, he sat down and touched his toes again, then twisted his torso left and right to make sure that he was as limber as he could be. “Alright,” he said, hopping up again. “I'm ready.”

Natasha gave him a look and told him to head to the free weights, where Steve picked up his usual fifty pound barbell- and was promptly told that Thor was babying him. “Fifty pounds?” She commented dryly. She wasn't _taunting_ him, per se, but the judgment in her voice was clear. “I can lift fifty pounds.”

Steve blinked and let his hand hover over the sixty pound weight, which she raised her eyebrow at, and then finally grabbed the seventy-five pound weight when she nodded in slight approval. She was going to kill him. Four sets (two per arm) later, Steve's biceps were buzzing and he was wondering how he was going to get out of this without collapsing in front of Natasha and making a fool of himself.

“What's your bench max?”

Okay, she couldn't judge him for this one. His max was pretty fucking good, alright? Thor said so! “Four hundred,” he said proudly, wiping his neck with his towel to ready himself for what came next.

Natasha nodded slowly, glancing at his chest and arms, then at the bench press. “Try four-thirty,” she said easily, sauntering off ahead of him and leaving Steve to pout as he followed. Four-thirty? That was a thirty pound increase- not just ten, not even _just_ twenty, but thirty! Laying his towel down, he laid back and planted his feet on the ground to get ready while Natasha adjusted the weight.

Deep breath. Gripping the bar, Steve pushed up with everything he had. It was a stretch, but after a few seconds he felt the weight lift and he pushed all the way up, extending his arms completely for a good ten seconds before he slowly let it back down. Breathing hard, he let his arms fall and found himself grinning up at Natasha, who hadn't said a word of praise yet.

It made him want to work even harder.

For the next thirty minutes, Natasha led Steve to a variety of different machines- leg presses, leg lifts, bicep curls, lat pull-down, step machine, treadmill. Steve was so thoroughly worked by the time they got to the push-ups that he needed another towel and really wished he'd worn shorts instead of sweatpants. Fuck.

“I want fifty push-ups,” she said firmly. “Followed by fifty crunches, and fifty squats.”

Natasha's gaze never left him. It never drifted to a phone or another person or even out the big windows overlooking the street below. Her eyes were always on him and, once he started his push-ups, she was touching him as well. “I want to see your nose touch the floor,” she said like it was no big deal. “Keep your back straight or I'll sit on it and you can lift the both of us.”

She would do it. Steve inherently knew that she would do it. “Is that what you want?” She asked. Her voice was so dry and quiet, but there was this authority in it that kind of made Steve want to do a whole lot more for her than these stupid push-ups. “If you can't do this, you probably can't fuck all that well.”

Say what? “What?”

“You heard me,” she countered. “Is that true? Is this the best you can do for me, Rogers?”

Fucking hell. “No, ma'am,” he said firmly, pushing himself a little harder to get through the fifty push-ups she'd requested and move on to the crunches. She watched him, slowly circling and appraising his performance the whole time. Steve vaguely wondered if she was this calculating in bed, if she would tell him he was doing it _wrong_ and demand that he do what she said.

Honestly, he found the thought oddly titillating.

It was when he moved on to squats that Steve realized Natasha was standing behind him instead of in front, and she'd moved close to touch his hips, leading him down into each deep movement and then back up. Maybe he wasn't the only one who was having slightly inappropriate thoughts? “You can do better than that,” she said. Okay, maybe not. “Squat like you're being paid for it.”

When he finished, Steve felt slightly off balance and knew he'd be getting a really, really satisfying eight hours of sleep that evening. But she wasn't through just yet. “My clients cool down with yoga,” she explained. “Not with a punching bag. So you're going to learn yoga.”

No choice there. Okay.

“I've never done yoga before,” he admitted, shifting his weight from foot to foot. “I don't think I'm that flexible.”

At least that got her to smile a little as she moved to stand in front of him, facing him dead on. “I'll help you, don't worry,” she said- kind of dangerously, in Steve's opinion. Nevertheless, he mirrored her pose and waited for instructions. Honestly, he was glad when those instructions were just to lift his arms and breathe in, then exhale slowly as he brought his arms back down. That was easy. There was no reason to be scared if yoga was just--- “Now step forward with your right leg and bend your knee, extending the other leg behind you. Arms out like this.”

No need to panic just yet. Steve carefully copied Natasha's pose and put his arms out for balance, glancing up to meet her gaze in some misguided attempt for approval. Nothing. Once they'd done the same pose for the other leg, she stood up straight and guided him into the one pose he recognized- downward facing dog. With his ass in the air and his head hanging, he hazarded another glance her way and found Natasha looking completely relaxed, though she was watching him. “Try to flatten your feet,” she told him, pulling herself up and moving to help him shift his legs forward so feet were flat like they were supposed to be. “And breathe.”

Steve tried not to react to Natasha's hands on his thigh, but it was really, really difficult. The next post was difficult too. Steve was told to balance all his weight on one leg, and then twist his other leg over his knee, and lift his arms over his head-- He couldn't lie, there was a lot of wobbling going on.

“Not so balanced, are you?” Natasha mused, standing in front of him with her hands on her hips. “Thor's got to work on developing your core.”

The next post she demonstrated was the same as the first- arms over his head, then letting out a slow breath while he lowered his arms. Then he was told to bend all the way forward and let his fingertips brush the floor. She wandered around him at that point, eventually giving a command to get onto his knees and slowly bend forward, effectively folding himself in half. By the time Steve's forehead touched the floor, Natasha was kneeling beside him, one hand on his back to guide him.

“We're going to take corpse pose for a while,” she told him. “Lay on your back...” They both did exactly that, arms at their sides, palms up, and Steve turned his head to watch Natasha until she told him he was supposed to be looking up and relaxing.

“But I am relaxed,” he countered- the first time he really talked back to her. “I don't need to meditate.”

Natasha huffed, sitting up to look down at him. “You just think this is nonsense, don't you? Probably thinking about how yoga's for women and you shouldn't have to do it.”

Steve sat up as well, bracing himself on his elbows. “No, I'm thinking that I'm already relaxed and--" 

Natasha rolled her eyes. "Oh, I know exactly what you're thinking. Big, strong men don't _do_ yoga, is that it? You'd rather be punching that bag until your knuckles bleed." 

Well, he had done that a few times, but-- "I didn't say it had anything to do with being a man. So what if women seem to like yoga more? I just don't think I need it, so I'm ready to head to the showers.” He wasn't trying to be rude, but he didn't understand why she was so intent on this whole meditating bit. “Is that okay?”

Pressing her lips together, Natasha stood up and shrugged, crossing her arms over her chest. Steve knew it wasn't okay, but she gave him a dismissive look and said they were done, so he thanked her and wandered off to the locker room so he could shower and head home. He was _certain_ he would be hearing about this from Thor next time... if he was back by then. If not, Natasha would likely take it out on him at their next session. As he stepped into one of the stalls and left his towel hanging near the curtain as usual, he wondered why it was that he had to be so goddamn stupid and open his big mouth.

As he rubbed his hands through his hair and let the cool water wash over him, he asked himself one other thing: Did Natasha think he was an idiot? She probably did. She didn't seem like the kind of trainer who tolerated people like him, people who questioned her and didn't want to sit through her long cooling-down session. And now she wouldn't look at him anymore and despite the fact that they hadn't had anything between them, he felt strangely like he'd lost something---

The curtain moved behind him and Steve didn't even bother looking back. “Someone's in here,” he said. “Find another one.” But the curtain didn't move again and he could distinctly feel someone standing behind him. Used to showering with guys on either side in the army, he turned without hesitation and found himself staring not at another gym member, but at Natasha. Natasha, who had stripped down save for the towel she'd tucked around herself. Natasha, who looked impossibly dangerous even in that moment, and it wasn't just because Steve was _naked_.

“What are you doing--?”

Natasha slowly peeled the towel away and Steve swallowed, letting his gaze wander over her as she hung the towel up beside his own. He had no words for how beautiful she was, everything toned just so, but she still had these soft, feminine curves around her hips and her breasts and he just wanted to touch..

“I know you want to,” she told him, stepping forward. “You think I haven't seen you watching me?”

Steve reached out without even thinking about it, settling his hands on her waist even as the water continued spraying over his back and shoulders. “Can you blame me?”

Natasha reached up with both hands, sliding them over his shoulders and pulling him down to her level. “No,” she answered, murmuring just loud enough for him to hear. “No, I can't.”

Their lips crashed together about a second after Steve backed her up to the wall beside them and Natasha wasn't shy about shifting her hold from around his neck to around his waist. Her hands found his ass and she squeezed hard, digging her nails in and using her grip to press their hips together and grinding hers forward at the same time. As the friction grew between them, Steve's body obviously responded the way she wanted it to- the way they _both_ wanted it to- and he ducked down to suck a light bruise into her shoulder now that he knew she wasn't against it, based on the scratches marring his ass.

At some point, she turned around and pressed her ass back, hands on the wall to brace herself. “You waiting for an invitation?” She panted, her hair now hanging in wet curls over her shoulder.

“No, ma'am.” Steve didn't have to be told twice. He stepped back just long enough to get himself into position and pressed right into her, gritting his teeth as he buried himself up to the hilt and held onto her waist for some kind of support. They worked up quite the rhythm together, Steve's thrusts hard enough to make her ass bounce and Natasha's movements back against him creating the delicious sound of skin on skin, echoing in the nearly empty locker room- 'nearly' being the key word there. Steve could still hear people shutting lockers and whistling to themselves, maybe getting dressed. He didn't want to think about what would happen if someone realized what was going on in their little stall.

Natasha's back was arched to a sinful degree, her whole torso curved to make sure that he was getting the best angle he possibly could. Steve didn't stop, didn't pause, didn't let up for one single moment at this point, half convinced this was some kind of fever dream and it wasn't really happening. The only moment when he had to cease for a second was when she pulled away and turned around, looping her arms around his neck with a meaningful look. Steve caught on quick, and he lifted her up against the wall, crowding against her while she reached between them to guide him into her again.

Again, the sharp sound of their skin slapping together echoed around them and regardless of the cool spray still hitting them, Steve felt like he was burning up. Natasha's nails digging into his shoulders didn't help that- if anything, the little bursts of pain just drove him on a little more and soon enough, he was grinding into her and one hand slammed against the wall of the shower while he held her up with his other arm and came hard, her ankles locked around his waist. He couldn't have escaped even if he wanted to.

When he was finished, Steve felt like he was still in a daze, but he carefully let her down on her feet-- and squatted down, practically falling to his knees in front of her and lifting her leg to hook it right over his shoulder. He didn't hesitate a single moment before burying his face between her legs and welcoming her hand in his hair, not to mention the pressure to somehow get closer. God, she was just pushing and pushing for more and he loved it, greedily licking into her and grabbing onto her ass to spread her open a little more.

At some point, Natasha reached up and grabbed onto the bar a little further up the wall meant for hanging shower supplies and the like. Biceps tensing, she picked herself up a little bit and Steve immediately supported her as much as he could, both of her legs over his shoulders and his hands under her as he concentrated all his attention on her clit. It took patience and dedication, but Natasha's thighs eventually tightened around his head and Steve just went for it, dragging his teeth lightly over the sensitive bundle of nerves before flicking over it with his tongue until she came, thighs trembling, her moans echoing enough to make him wonder if anyone had caught on yet.

When he set her down this time, Natasha looked a little unsteady and leaned into him, shivering slightly. It was probably just an after shock, but it gave Steve the opportunity to rub her back and smile to himself. Maybe this was the start of something great. Even as she reached out to turn off the shower, he was thinking about maybe asking her out for coffee or just having her over so they could do that again, or--

“Good job,” she told him, reaching up to lightly pat his cheek with the palm of her hand. “See you next on Wednesday. Same time, maybe not the same place.” Natasha smirked and winked at him before grabbing her towel and slipping right back out of the stall, leaving Steve to stare after her. Wait. But--

The whole thing puzzled him. Was she really just planning on fucking him once and moving on? Because he wanted to get to know her a whole lot better, maybe have sex in a _bed_ , definitely spend at least an hour or two going down on her. For the rest of the night and all through Tuesday, he was questioning exactly what kind of reception he was facing when he walked into the gym.

When he arrived, he found that Thor was still absent for the time being and Natasha sauntered over to him wearing her usual tights, along with a red sports bra and a black hoodie. She was all business for the duration of their workout, pushing him to his limits and then some, insisting upon cooling down with yoga- and he didn't protest this time.

At the end of their workout, he was drenched in sweat again and Natasha just told him to hit the showers. Nothing else. Steve wondered if maybe he hadn't been what she wanted in a bedroom sense, so maybe this was her way of rejecting him? Except she'd made it sound like they'd be doing this again.

The locker room was deserted this time because he'd come at a pretty slow time of day and Steve was just securing the towel around his waist to walk to the showers when he heard the click of the lock on the door and turned to find Natasha there again. There was still no explanation, but she walked up to him, slid her hands over his bare chest, leaned forward to lick a stripe up from his collarbone to the hinge of his jaw, and gave him the most openly indecent look he'd ever seen.

And that was how they wound up having sex right there, with Natasha bent over the bench and Steve kneeling behind her. It was fast and hard and _filthy_ , but it didn't seem like either of them cared very much. Steve got Natasha off with his fingers this time and he came just as hard as he had on their first foray into unexplained locker room sex, pitching forward to taste the sweat between her shoulder blades as he came down from it all.

Panting, he finally found the courage to ask what he'd wanted to ask before. “Can I buy you coffee sometime?”

Natasha shifted and he pulled out, standing up and offering his hand to her while she got up as well. She was silent as she dressed, pulling on panties and tights, sports bra and a tank top she pulled from nowhere. Steve grabbed his towel and tucked it around his waist just because he didn't want her to be the only one of them who was clothed. “No,” she answered when she'd adjusted herself and grabbed her hoodie, shrugging and turning on her heel to walk away.

Steve frowned, but she stopped at the door and looked over her shoulder, giving him a mischievous grin that spoke of a future of _some_ kind, and promises he couldn't describe with words. He had to smile in return, even ducking his head briefly when she finally left him. This wasn't over. Not yet. And if he had any say in the matter, it wouldn't be over for a very, very long time.

 

**Author's Note:**

> Thanks for reading! <3


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